Impregnation of poplar wood with multi-functional composite modifier and induction of in-situ polymerization by heating

Herein, a modified wood with greatly improved mechanical properties and reduced hygroscopicity was successfully prepared. The effects of the impregnation of multi-functional composite modifier on the chemical, thermal and morphological properties of poplar wood were also studied by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analyzer (TGA) and Scanning Electron Microscopy- Energy-Dispersive X-ray Analysis (SEM-EDXA). The multi-functional composite modifier was fabricated by methylolurea, dimethylol dihydroxy ethylene urea (DMDHEU), carbamide and silica sol. Cross-linking reaction happened between the wood cell wall and the multi-functional composite modifier. The position peaks in the XRD pattern didn't change obviously, which indicated the crystal structure of cellulose was not noticeably affected by the chemical modification. The FT-IR analysis showed that the intensity of hydroxyl (-OH) and carbonyl (C = O) absorption peaks decreased, which was attributed to the -NHCH2OH of the modifier reacted with the hydroxyl and carbonyl of the wood. Meanwhile the Si-O-Si bond and Si-O-C bond formed between the wood structure and silica sol by in-situ polymerization. The TGA curve showed the thermal stability of the modified wood. The micrographs and major elements of the untreated and modified wood were observed by SEM-EDXA.